True-rolling tube or rod bending tool



J. A. TAYLOR TRUE-ROLLING TUBE OR ROD BENDING TOOL May 18, 1954 s Sheets-Sheet 1 Filed April 5, 1951 V INVENTOR. JLHJE [0/- May 18, 1954 J. A. TAYLOR 2,678,573

TRUE-ROLLING TUBE OR ROD BENDING TOOL Filed April 5, 1951 3 Sheets-Sheet 2 LEgL 15L INVENTOR.

2 Jam 7 h- May 18, 1954 J. A. TAYLOR TRUE-ROLLING TUBE 0R ROD BENDING TOOL 3 Sheets-Sheet 3 Filed April 5, 1951 plane of the circle.

Patented May 18, 1954 TRUE-ROLLING TUBE OR ROD BENDING TOOL John A. Taylor, Evansville, Ind.

Application April 5, 1951, Serial N 0. 219,443

9 Claims.

This invention relates to mechanism for shap ing work pieces and particularly to mechanism in the form of a tool for bending tubes, rods, channels and other shapes.

The conventional so-called tube-bending tool comprises a pair of relatively movable parts, one of which has an arcuate edge about which the tube is bent. The part having the arcuate edge customarily has a hook or roller for engaging the tube so that as the parts are moved relatively the tube is bent by a wiping action around the rcuate edge. The interconnection providing for relative movement of the parts comprises a pivot; hence, the tube is subjected to a pulling action which results in scratching of the tube unless a roller or some other antifriction means is used. Moreover, because the pivot provides a fixed axis of rotation, the conventional tool is inefficient and does not employ the best available mechanical advantage.

According to the present invention these disadvantages are eliminated by the provision of a mechanism in which relatively movable parts are interconnected by utilization of the principle ofthe cycloid curve. A cycloid curve, by definition, is a curve traced by a point spaced from the center of a circle rolling along a base line in the If the point is within the circumference of the circle, the cycloid curve is prolate; if the point is on the circumference of the circle, the result is an ordinary cycloid curve; and if the point is outside the circumference of the circle (that is, on a prolongation of a radius of the circle) the cycloid curve is curtate.

In the utlization of this principle, the prime advantage gained in a mechanism of the character referred to is that the parts are interconnected not by a fixed axis but bymeans permitting rolling movement of one part relative to the other, whereby the work piece (such as the tube, rod, channel or the like) is wrapped rather than wiped around one of the moving parts into its desired shape or bend.

The adaptation of mechanism utilizing interconnecting means of the nature referred to is best served by the provision of a mounting surface on one of the members having therein a pair of angularly related interconnected slots based respectively on two prolate cycloid curves traced by two points spaced equidistantly from the center of a circle rolling along a straight base line. The base line is utilized for the location of a supporting block which holds the workpiece in its straight or initial stage. The are of the circle represents, the desired shape of the bend to be produced in the workpiece. In short, the angularly related slots serve as tracks on. one part of the tool and the other part of the tool is mounted for rolling movement by means of track followers thereon which respectively engage the tracks. The part having the track followers is the part that has the arcuate edge referred to above.

It is another object of the invention to provide a tool that is simple in construction, easy to use, and inexpensive to manufacture. Another object resides in the arrangement of an extension at the intersection of the slot or track means so that the parts of the mechanism may be moved in a separating direction to permit initial introduction of the work piece.

The foregoing and other important objects and desirable features inherent in and encompassed by the invention will become apparent from the following detailed description of preferred embodiments of the invention as illustrated in the accompanying sheets of drawings in which:

Figures 1, 2 and 3 are schematic views showing the geometery involved in the development of the mechanism selected as the most practicable for the majority of situations.

Figures 4 and 5 are perspective views of one side of one form of tool showing two successive stages in the operation of the tool in the forming of a bend in a tubular work piece.

Figures 6 and 7 are views similar to Figures 4 and 5 but taken from the opposite side of the tool.

Figures 8, 9 and 10 are elevational views, partly in section and on an enlarged scale, showing successive stages in the operation of the tool.

Figures 11 and 12 are respectively side and end views of the arcuate or arbor part.

Figure 13 is a sectional view on an enlarged scale as seen along the line |3l3 of Figure 5.

Figure 14 is an elevational view of a modified form of part in which the slots used have straight rather than slightly curved sides.

Figures .1 through 13 cycloid curves forming the basis of the preferred embodiments of the invention herein disclosed are prolate. As will be hereinafter brought out 3 in greater detail, the curves chosen are those which approach a straight line. For all practical purposes, as will likewise be hereinafter developed, straight lines may be used if desired. In Figure l, a circle 0, having a center 0, is tangent to a line y-y at an initial or starting point 8. A line 11-11 is erected perpendicular to the line.y-y at the point s and, of course, intersects the center of the circle. One diameter D is coincident with the line d-d. A second diameter D is at right angles to the diameter Q and lies along a line 03-00 that passes through the center 0 of the circle, and that is, of course, parallel to the line y'y. I

Assuming that the circle 0 rolls along the base line yy in the direction of the arrow indicated, the object is to permit the circle to roll through an angular range of 90; that is, from the position of Figure 1, through that of Figure 2, to that of Figure 3. This degree of rolling will be accomplished when the diameter D is coincident with a line e-e parallel to the line d-cZ. The line e-e represents the stopping or final position of the circle in its rolling motion through 90.- On the circle itself, the final position is represented by the letter t; a midway point is represented by the letter 12-. e

Points a and b are selected on the radii 0d and 0t. Asstated above, the most'practical locations for these points a and 1) occur where the prolate cycloid curves traced thereby approach straight lines, each at an angle of 45 with the line x-m, leaving an included angle of 96 between the approximately straight lines. The distance ca (or ob) that will most nearly satisfy this condition 'is found to be equal to approximately one-eighth of the circumference of the circle a. V

' Figure 2 shows the beginning of the tracin of two cycloid curves (2 and 16 between points a. and b respectively as the circle rolls to an intermediate position wherein 'thepoint p is tangent to the line y y midway between the lines dd and ee. The diameters D and D intersect the line 03-31: at 45.

Figure 3 shows the completion of both curves (1 and b The point a has now moved to the point on the line 33-33 initially occupied by the :point 12. As will be seen, the prolate cycloid curves 0, and b quite closely approximate straight lines, particularly in the zone of their intersection with each other and with the line x:r.

Figures 4 to vl3 show the incorporation of these principles into a preferred mechanism or tool for bending a worl; piece W, hereinrepresented as a tube. But it will be understood, of course, that other sections, such as rods, channels and the like, may be shaped in the manner disclosed and suggested,

The mechanism or tool comprises a first member 26 having a handle 22 and a head or support 24 which presents a generally fiat mounting surface 26 lying in :a plane. The first member iurtherincludes a block portion or element 28, rigidly fixedthereto as by recessed screws 39 and provided with a work-piece-engaging channel or groove 32. Opposite sides of thechannel are bordered by straightedges 3-5. Either of these .edgesmay be considered as ,lying along or representing the, lineyy -(Figures 1 to 3 and 8 to .10).

The support or head 24 provided with a pair of track;or slot means 36 and 38. These are based respectively on the prolate eycloid, curves ailand 19 of Figure 3 and are best shown in Figures.8,..9 andlO. .In these figures, the main of thehandle hl.

construction lines used in Figures 1, 2 and 3 are incorporated for the purpose of orientation of the slots 35 and 33. It will be noted that these slots or tracks are centered exactly on the curves a and b and are therefore defined by curved sides respectively parallel to the curves. The slot or track means intersects substantially at a. angle andeach is at substantially a 45 angle to the line a:-:r. The slot 35 is carried beyond the point of intersection to provide a short extension do in the direction away from the line y-y, for purposesto presently appear.

The other part of the mechanism or tool comprises a second member 42 in the form of a formmember equipped with a handle 44 and mounted on the support 24 of the first member .28 by'means comprising a pair of track elements or followers 46 and 48 respectively received by and following the slots or tracks 36 and 38. As best indicated in Figure 9, the followers and 48 are initially located so that their centers fall respectively on the points a and b.

From the description thus far, it will be seen that the mechanism just described duplicates the geometry illustrated in and described in connec tion with Figures 1, 2 and 3. The second mem ber &2 has an arcuate edge 53 which is a'section of the circle '0 and which is therefore tangent to and in effect rolls along the line y- -y (represented in the tool by one of the straight edges 36.). Thearcuate edge portion 50 is formed as a groove or channel 52 to receive the other side of the workpiece W (Figure 13 M The construction of ,each of the followersjis represented bythe details in Figure 13, wherein it is shown that theremay be utilized a cap screw 55 threaded into the member'42 and carrying'a roller 56 to provide antifriction means in the track or slot. A washer 58 mayb'einterposed between thehead of the screw 54 and the outer face of the. support 24.011 themember 2t.

Thefstraight workpiece is initially laid in the position shown in "Figure "8. The extension ill) in the trackmeans accommodates the follower.

as the member '42 is shift'edbodily infa direction 6D providing means for engaging the oppfisite side of "the work piece. When, the work piece is positioned as in Figure 18,.th'e'inembers 2 .0 and 42 .ar'e'moveii ,tog'therf'to assume the "startin positionfofjFiguref9. The work piece, "is ithen received by thelgr'oove 'or channel. 32 in the block 28 and'is engaged inlitsother side by .tlie'channel I52 Li'nfthe "member 42 at the point As the member-.142. is rolled ']to the Position of Fi urel'Ofthe work. piece ."is wrapped "about the arcuate edge 50. Rolling" rhovmentLisjof course, achieved by movement of the "followers .45 and i8 respectively along the ,trackfor slot "means 36 and 38. Since this motion isicontiolled bythe tra el; and iollower mechanisrmflthere,Willjbe'iio slippage of .worl; piece relative tojthe member 42 and henc'e thhere, will. be no "longitudinal stretching or scratching off the workpiece.

. "Ihe'm ember 42 isirelievd adjacentthe'hook 6i) as at 52 to'faci1 i'tate insertion, and: removal. of the work piece. In' the detailoffthe partor' member 42 in Figure l1, the humerals .64 indicate tapped bores fo receiving the capscrew 541 for the followers 41$:and 1' 8. The numeral 65 indicates a tapped tapered bore for receiving onelend The handles 22 and d l on the membisibiesent means connected respectively to the members for moving the members relatively in the rolling motion described above. It will be understood, of course, that such means is only representative and could be carried further in the application of power to mechanism embodying the principles disclosed herein.

Figure 14 Mention was made above of the fact that in a practical application in the. principles of the invention, the slots based on the prolate cycloid curves could be made straight. A modified form of first member I20 is shown in Figure l. The reference numerals used in this figure are the same as those previously used except that they are prefixed by the numeral L Thus, the member I20 has a handle I22, a support or head I, a mounting surface I26 and track or slot means I36 and I38, including an extension I40 beyond the intersection thereof. The numerals I30 indicate tapped bores for receiving cap screws for the mounting of a block in the manner shown at 28 and 30 in the figures previously described. The lines of construction used in Figures 1, 2 and 3 are applied to the figure to further illustrate its identity with the construction first described.

Summary The fundamentals of the operation of either of the forms of invention have, it is believed, been adequately set forth above and need no further elaboration. One of the important points to note is that for all practical purposes, the particular prolate cycloid. curves utilized could be carried into straight slot or track means, as shown by a comparison of Figures 8 and 14, for example. Accordingly, the use of such expressions as approximately straight here and in the claims is intended to cover equivalents engendered by the proposition just stated. Further, although the invention has been disclosed as a manually operated tool, the mechanism involved may be considerably amplified for incorporation into powerdriven apparatus.

Many other modifications and alterations in the preferred embodiments illustrated will undoubtedly occur to those versed in the art, all without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. Mechanism for shaping a work piece, comprising: a first member having an edge defining a straight-line path; a second member having an edge formed as an arc of a circle tangent to said straight-line path; said members being arranged for relative movement so that the second member rolls on its arcuate edge along the straight-line path of the first member with said arcuate edge always tangent to said path; a support fixed to one member and having therein a first track means following the cycloid curve of a first point on a radius of the circle of which said are is formed, and having also a second track means following the cycloid curve of a second point on another radius of said circle; first and second track followers on the other member respectively at said first and second points and respectively engaging said first and second track means; said members being respectively formed along said edges to receive therebetween a work piece to be shaped according to one of said edges by relative movement of said members as aforesaid; and means connected respectively to the members for effecting relative movement thereof.

2. The invention defined in'claim 1, further characterized in that: the radii on which said first and second points are located are at right angles to each other; and said points are equidistant from the center of said circle.

3. The invention defined in claim 2, further characterized in that: said points are located within the circumference of the circle so that the cycloid curves are prolate.

4. The invention defined in claim 3, further characterized in that: the distance between each of said points and the center of said circle is on the order of one-eighth of the circumference of said circle whereby each of said prolate cycloid curves approaches a straight line and said curves intersect at an angle of approximately to each other.

j 5. The invention defined in claim 4, further characterized in that: one of said radii is at right angles and the other is parallel to said straight line path at the starting position so that the intersection of each curve with a prolongation of said parallel radius is at an angle of approximately 45.

6. The invention defined in claim 5, further characterized in that: one of said track means is extended beyond said intersection of the cycloid curves to accommodate extra movement of its respective follower so that the members may be shifted relatively away from each other to temporarily space the arcuate edge of the second member from the straight-line edge of the first member.

7. Mechanism for shaping a workpiece, comprisin a first member having a support fixed thereto and presenting a mounting surface lying in a plane; first track means on the support shaped as part of a cycloid curve traced by a first point spaced from the center of a circle lying in said plane and rollin alon a line in said plane from a starting position; second track means on the support shaped as part of a second cycloid curve traced by a second point spaced from the center of said circle rolling along said line from said starting position; means on the first member generally aralleling said line for engaging one side of a work piece to be shaped; a second member; means mounting the second member on the support for rolling movement relative to the first member, including first and second track followers located respectively at said first and second points and respectively engaging said first and second track means; means on said second member for engaging the opposite side of such work piece and complementin the work piece-engaging means of the first member to shape the work piece as the members are relatively rolled as aforesaid; and means connected respectively to the members for eifecting relative rolling thereof.

8. Mechanism for shaping a work piece, comprising: a first member having a support fixed thereto and presenting a mounting surface lying in a plane; first track means on the support based on a first prolate cycloid curve traced by a first point spaced from the center of a circle lying in said plane and rolling along a straight base line in said plan through an angle of approximately 90 from a starting position to a final position, said first point lying on a first radius of said circle that is perpendicular to said base line in the startin position of said circle and being spaced from the center of said circle on the order of one-eight of the circumference of said circle so that said curve closely approximates curve of substantially the same length as the first curve and traced by said second point in the'rolling of'said circle along said base line from said starting position to said final position, said second curve likewise closely approximating a straight line at an angleo'f approximately 457 to said base line so that the included angle between said curves is on the'order of 90, said second track means having spaced apart, par- ,aillelj approximately Straight sides substantially centered on said second curve and defining a track-slotgenerally coextensive with'said second curve; saidtrack slots intersecting at saidsecond point to provide a continuous V-shaped track: meansonthe" first member lying generally par- .all'el to said base line and shaped to support a Work piece lying along said base line;- a: second member; means mounting the second member the first member; including a-pair' or" track an wers on thesecondmember" spaced apart on the order of said first and second points and respectively running in said first and second track slots to efiect rolling mounting of said second ifieinber on said support, said second member havi- 'n-gmum means thereon for engaging the were piece supported by the means on the first member, said arcuate' means being formed about the center of said circle and extending on the order of 90 coincident with the angular range of rolling of said circle alon said baseline; and means connected respecti'i'iely to the first and second members for effectin rolling of the second membr-rel ative to'the-first.

9 2A tool for forming an arcuate bend in a work piece such as a tube, rodor the 3 7 like, comprising: a first member havingivthereon amounting surface lying in a plane; a econd member positioned alongside said mountingsurface'and: having a workpiece-engagin portion shaped as an arc ofa circle lying in said-plane and representing the arc of the-bend to beformed in the work piece; means mounting: the-second member on the mounting surface, including a pair of angularly related slot means in the mountingsurface'based respectively on a pair of cycloid curves traced respectively by a pair of points spaced from the center of said circle as said circle rolls along a straight base line in said plane, and apairof followers'on thesecondmemS- ber respectively at said points and respectively following said slotmeans; means on the first member providing a straight portion parallel'to said base line for supporting the work piece between said straight portion and the arcuate portion of the Second member; means connected respectively to themernbers for moving the-secand member relative to the first member in a rolling motion controlled by said slot means and followers; and means connected to the second member for engaging the work piece to pickup the work piece and bend it around said arcua't'e portion as'said second member is rolled as aforesaid.

References Cited in the file of this patent UNITED STATES PATENTS 

